[leetcode]Word Break

新博文地址：[leetcode]Word Break

 

Word Break

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.

For example, given
s = "leetcode",
dict = ["leet", "code"].

Return true because "leetcode" can be segmented as "leet code".

 好奇怪，这道题很早之前做的，为啥没有写博客呢。反正没啥难度，现在补一下吧

 public String reverse(String s){
		StringBuilder tem = new StringBuilder();
		for(int i = s.length()-1; i >= 0; i--){
			tem.append(s.charAt(i));
		}
		return tem.toString();
	}
    public boolean wordBreak(String s, Set<String> dict) {
        
		s = reverse(s);
		Set<String> set = new HashSet<String>();
		for(String tem: dict){
			tem = reverse(tem);
			set.add(tem);
		}
		
		if(s == null){
			return true;
		}
		if(s.isEmpty()){
			return true;
		}
		for(String tem : set){
			if(s.startsWith(tem)){
				String subString = s.substring(tem.length());
				if(wordBreak(subString, set)){
					return true;
				}else{
					continue;
				}
			}
		}
		return false;
    }